Reptiles and Amphibians in Britain

Extract

In Britain there are three snakes, three lizards, three frogs (two of them introduced), two toads and three newts. This poor list, only fourteen species, can be explained by the intense cold of a past Ice Age, during which it is doubtful whether any of these cold-blooded creatures survived. If not, they must have returned after the melting of the snows and glaciers. During the great thaw Britain was for some thousands of years still connected with the Continent. Then, as the sea-level rose and a certain amount of earth-sinking took place, much of the land became waterlogged. Finally, about 8,000 years ago, the last land bridge was severed, the sea cut through to form the Straits of Dover, and Britain became an island. It should be noted that all our species are found also on the Continent, and that they diminish in numbers and species as one travels north. Ireland has the poorest supply, since it was the first to break away.